B.—CHEMISTRY. 63 
the heat treatment of which in relation to its mechanical properties has been 
the subject of close study, resulting in improved gun forgings being delivered 
by the makers. Two main types of steel have been under consideration, 
_ those which would give a minimum yield point of about 35 tons per square 
inch when treated in large masses, and those at about 25tons. Asa result 
much information has been acquired on the properties and heat treatment 
of steel containing various proportions of nickel, chromium, moly- 
bdenum and vanadium. The study of the elastic properties and of the 
- erosion of gun steel has been of importance to gunnery. The Moore adap- 
tation of the Brinell hardness test, in which a small ball and load are used 
ina specially designed machine, was originally developed in the Department 
for testing small-arm cartridge cases, and has since found many other 
important applications here and elsewhere. 
Among other investigations on non-ferrous metals, those on ‘ season- 
_ eracking ’ of brass and its prevention, and on methods of extrusion, have 
been productive of useful results, and in connection with the Non-Ferrous 
Metals Research Association, work is in progress on the casting of brass 
to produce sounder ingots, on the die-casting of brass and bronze, and on 
the failure of lead cable sheathing by cracking. 
During the war, the use of substitutes, the easing of specifications to 
increase output with safety, the examination of enemy ammunition, and 
the tracing of causes of failure and discovery of remedies provided a large 
field for investigation. 
The other aspect of metallurgy of special interest to the State, that of 
_ minting, has a long history ; from early times the need for a high and 
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uniform standard of coinage, and the crime of debasing it, have been 
recognised. The difficulties that confronted the early assayers, without 
methods of quantitative analysis and with no fine balances, are apparent 
from the description of their methods, but it may perhaps be held that 
these needs as they became borne in on the early assayers and their 
frequent collaborators the alchemists, led the way to the appeal to weighing 
in chemical work. 
As early as 928 A.D. laws were proclaimed by King Athelstan appointing 
“mynteres ’ whose products were scrutinised at the trial of the pyx ; later, 
in 1180, supervisors of the coin manufactured by ‘moneyers’ were appointed. 
An official mention occurs in the reign of Edward I. of a Guild of 
Goldsmiths in London, which had, however, existed since 1180, in an Act 
providing for the assay of silver vessels by the Wardens of that craft. 
The earlier writings on the subject of assaying are those of Germans, of 
whom Queen Elizabeth brought over a number to introduce their methods 
and assist in the development of the resources of the country. 
The course of testing seems to have been originally by means of the 
touchstone, supplemented much later by observing the effects of acid on 
the trace left by drawing the metal over the stone, the method of deter- 
mination of density, the cupellation method, officially recognised by 
Henry II., and finally the wet method of analysis. 
To safeguard the fineness of the coinage a King’s Assayer was appointed 
in 1222, a Master of the Mint manufacturing the coin under contract, and 
a Warden acting on behalf of the King. A Commission, having toured 
the Continental mints, reported in 1870 in favour of the present organisa- 
tion of the Chancellor of the Exchequer being Master of the Mint in virtue 
